I sometimes regret that I can't decide to work more at home and from the imagination. Certainly, imagination is a capacity that must be developed and that enables us to create a more exalting and consoling nature than what just a glance at reality (which we perceive changing, passing quickly like lightning) allows us to perceive.
       - Van Gogh in a letter to French painter Emile Bernard, 12 October 1888

Imagination is a capacity that must be developed.

Jung encouraged his patients to set aside part of the day for what came to be known as ‘active imagination’. This is a state of reverie, in which judgment is suspended, but consciousness is preserved. The subject is required to note what phantasies occur to him, and then to let these phantasies pursue their own path without conscious intervention. In this way, the subject may be able to rediscover hidden parts of himself as well portray the psychological journey on which he is embarking.
- Anthony Storr, Solitude, A Return To The Self

I set aside at least half an hour a day, eyes closed, for reverie. Or walking in the woods, daydreaming. Or both. It helps me focus on what's important. And avoid what's not.

It is only innately mechanical, salami-factory novelists who set such great store by research; in nine cases out of ten what natural knowledge and imagination cannot supply is in any case precisely what needs to be left out.
      - John Fowles, author including The Magus and The French Lieutenant's Woman

I don’t agree with Fowles that research has no value, even in the creation of fiction. Fiction based on in-depth research is often interesting, and valid creative work. But I agree with Fowles that the most valuable, interesting creative work arises, somehow, out of our imagination. Some of Fowles’ best work arose out of his experiences and research, but his truly transcendent work came from his imagination.

...imagination, we have it because we don't have enough without it.
     - Wallace Stevens.

Without imagination, humanity is pretty unremarkable.

A creative person is one who enjoys, above all else, the company of his own mind.
      - Denise Shekerjian, Uncommon Genius

That ability to retreat into our own mind, our own reality, and to fiercely protect that time, is part of what can make us, as creatives, unreasonable, and difficult to live with.